$0D MAF Tunning help

[Kadams87]

I have performed a MAF Swap in my 92 Chevy K2500. I have worked out the electrical and ads stuff with Dimented24x7's help. I will email my bin with the ads to anyone willing to look at it.

Here are the specs on my setup:
4 Bolt Main 400 Bored .60 over=413
ProComp Aluminum 190cc Intake 64cc Combustion Chamber 2.02 intake/1.60 exhaust
Full Roller Rockers 1.6 ratio
Holley Pro-Jection Throttle Body Injection Manifold
COMP Cams Xtreme Energy 12-262-4 – 114 LSA, .464 intake lift, .470 exhaust. With the 1.6 rockers the final lift at the valve is .495 intake/.501 exhaust
Bored Out 50mm TBI
90hr/lb 454 Injectors @ 21 PSI
NV4500 5 Speed Manual
255gph fuel pump
New GM Distributor
Headers
COMP 981 Valve Springs
COMP .080 7.2 Pushrods
SCAT 400SBC Cast Crank
ProComp 5.7 I-Beam Rods rated at 550 HP
9.5:1 .60 over SpeedPro Pistons
EGR Disabled and 160 thermostat
Heated NB 02 and Wide Band 02

This is my first tuning adventure and it is kickin my butt. I am messing with stuff but there are some problems that are killin me.

1st My idle goes up to 1500 like clockwork when I push in the clutch until the vehicle comes to a stop. If I am coasting long enough the idle will start moving between 1500 and 900. It hangs up there until I have been at a stop for about 4 seconds.

2nd The AFR's aren't where they are supposed to be I think. At idle they are showing 11-13. As soon as I touch the gas they bump up to 13.5-15. Even cruising yields 14.3-15.4. When I floor the truck it goes up to about 17/18 and after about a second they come down to about 14.3. I can't get them to richen up anymore than that.

The bottom end is decent but you really feel it struggle on the top end. I couldn't break 96 mph the other night on flat freeway. Pull it down to 4th and the motor doesn't work as hard to maintain speeds. I just got my WB02 scaled correctly in the bin so I will be able to to datalog with TunerPRO RT now and have all the info in there.

Anyone at all I am all ears as I don't know what I am doing but I want to get this thing running right before winter really comes on out here.

Also anyone in Idaho that has any experience with this, I will bring the truck to you if you are willing to look at it.

[drumer919]

Originally Posted by Kadams87

2nd The AFR's aren't where they are supposed to be I think. At idle they are showing 11-13. As soon as I touch the gas they bump up to 13.5-15. Even cruising yields 14.3-15.4. When I floor the truck it goes up to about 17/18 and after about a second they come down...

You may need to turn your injector sizes down a few lbs, that will trick the PCM into leaving them open longer and getting more fuel.
Or you could try turning the pressure up without changing the inj constant, that would also get more fuel. If its going lean on tip in you need to get some more AE in there though, thats definitely one of your problems.

Sorry I dont know much about the MAF code, do you still use the VE tables as a base or are those gone?

[Kadams87]

The VE Tables are still there but they aren't used unless the MAF sensor throws a code. I am already rich when I let off the throttle and at idle so I don't want to bump the pressure anymore. I was driving last night and my BLM's seem high, 131-133.

I added some AE guess I need to throw more at it. Could it take alot more than stock? Is there anything that would need to be done with the PE?
I am going to try and do some datalogging after work and hopefully shed some light on this whole ordeal.

[drumer919]

Yes, I had to increase both my AE tables 10 fold, maxing parts of them out to finally get it right.

133 isnt THAT bad, I'd say BLM +/- 10 would be considered ok and +/- 5 would be very close.

One thing I like to do while tuning is to set my commanded AFR at 14.7 at all conditions, that way its easier to tune cause you dont have to worry about what your commanding at that moment and have to figure out how far off you are from that.

Here are my AE tables from back when I was still TBI, I was able to go way down now that I'm PFI. HTH
http://i452.photobucket.com/albums/q...romTBIdays.jpg

[Kadams87]

Could you explain how to command that. The stoich is set to 14.7

[drumer919]

First Enable 400D-Bit 0 Open Loop AFR Enable, then set the Open Loop AFR vs Temp vs Vac , fill the table with 14.7.

Also disable DFCO by setting one of the params to something that will never be met.

Did you see the link I added to my last post? I may have got a ninja edit in on you.
Edit:Photobucket decided to make the screen shot so small you cant read it, sorry.

[Kadams87]

Open Loop AFR is already turned on so I will change the table.

The image is too blurry when I zoom in on it